.cover{
    margin: 0 auto;
    width: 1200px;
    min-height: 100vh;
}

.box1{
    height: 400px;
    width: 100%;
}

.willRotate{
    transform: rotate3d(0,1,0,180deg);
    -webkit-transform: rotate3d(0,1,0,180deg);
    -moz-transform: rotate3d(0,1,0,180deg);
    -ms-transform: rotate3d(0,1,0,180deg);
    -o-transform: rotate3d(0,1,0,180deg);
}